The present invention relates to a sensor device with a flexible electronic conductor structure for integration in an electrical circuit, which has an insulating layer, on which an electrical conductor structure is mounted.
These types of device are known in a variety of forms in practice and can be integrated in a more complex electrical circuit by connection to further components, for example, to a test circuit, a power source, a sensor or the like. During production, until now, for example, a substrate is used as an insulating layer, on which the conductor structure can be pressed. The substrate can be a printed circuit board or also a flexible film, such as the products distributed under the tradenames Flexfoil, Kapton, Ito-Film, and Melinex. The substrate is pressed with an electrical conductive dye, which can include conductive components, such as silver, copper, conductive polymers, graphite, graphene, or the like, for forming the conductor structure. Alternatively, the conductor structures can be made also according to an etching technique, a vapor deposition technique, or a stamping technique. If the insulating layer is made from a film or from paper, in addition, an adhesive layer can be provided, so that the device provided with the electrical conductor structure is self-adherent, and for example, like an RFID label, can be fixed to a background, in particular, a device, a library book, or the like.
Until now, the application of electrical conductor structures using printing methods, in particular, a screen process, was limited to specialized substrates. With substrates, which must fulfil further functionalities, for example, the absorption of moisture, it is not possible to print the electrical conductor structures. The limitations for printability are provided, in particular, in that a background structure does not permit a continuous conductive printing, that the related substrate has no adequate heat resistance in order to endure a drying process without being damaged, that the substrate has no adequate surface voltage for a printing process, that the substrate with regard to its shape, its curvature, and/or its grammage is unsuitable for a printing method.
In WO/9960820 A2, a printed electrical circuit is described, which contains a printing support comprising a flexible, flat and electrical insulating material, which is imprinted on both sides with electrical conductor tracks, whereby the conductor tracks of the two sides can be connected to one another in an electrically conductive manner by at least one opening in the printing support. The electrical conductor tracks printed onto the support medium serve exclusively as current conductors, without having any sensor properties.
In EP 2 267 218 A1, a multi-layer label is provided, which can be imprinted or fused on using the effects of heat onto a piece of clothing. An RFID (radio frequency identification device) can be integrated into this label. This RFID has no sensor properties.